Officials investigate who launched missile

July 17, 2014 at 2:17 a.m.

People inspect the crash site of a passenger plane near the village of Grabovo, Ukraine, on Thursday. Ukraine said a passenger plane carrying 298 people was shot down Thursday as it flew over the country, and both the government and the pro-Russia separatists fighting in the region denied any responsibility for downing the plane.

WASHINGTON (AP) - American intelligence authorities believe a surface-to-air missile took down a passenger jet in eastern Ukraine on Thursday, a U.S. official said, but the Obama administration was still scrambling to confirm who launched the strike and whether there were American citizens killed in the crash.

Vice President Joe Biden said the incident was "not an accident."

Among the unanswered questions was whether the missile was launched from the Russian or Ukrainian side of the border they share, according to the official, who was not authorized to discuss the matter publicly by name and insisted on anonymity. But the official said U.S. intelligence assessments suggest it is more likely pro-Russian separatists or the Russians rather than Ukrainian government forces shot down the plane.

The U.S. has sophisticated technologies that can detect missile launches, including the identification of heat from a rocket engine.

Following the crash, the Federal Aviation Administration said U.S. airlines voluntarily agreed not to operate near the Ukraine-Russia border. The agency said it was monitoring the situation to determine whether further guidance was necessary.

The incident came one day after President Barack Obama levied broad economic sanctions on Russia as punishment for its threatening moves in Ukraine. Moscow is widely believed to be supporting pro-Russian separatists fomenting instability near the border, though the Kremlin denies those assertions.

Anton Gerashenko, an adviser to Ukraine's interior minister, said on his Facebook page that the plane was flying at an altitude of 33,000 feet when it was hit by a missile fired from a Buk launcher.

U.S. officials said Russia has sent a wide range of heavy weaponry into eastern Ukraine in recent months, although it is uncertain whether that includes the Buk air defense system, which is operated by a tracked vehicle. The U.S. suspects that Russian shoulder-fired anti-aircraft weapons have been provided to the separatists.

According to a Ukrainian state-owned import-export firm that specializes in military technology and weaponry, known as Ukroboronservice, the Ukrainian military operates the Buk-M1 system, which is designated by NATO as the SA-11 Gadfly. It is designed to shoot down military aircraft, including helicopters, as well as cruise missiles.

The Russians also are believed by U.S. officials to have provided the separatists in eastern Ukraine with other heavy weaponry such as artillery, multiple-launch rocket systems, tanks and armored personnel carriers.